Magnetic catch



' March 20, 1962 A. w. AHLGREN MAGNETIC CATCH Filed Oct. 21, 1957 mvslorom 3,926,134 Patented Mar. 20, 1952 ice 3,026,134 MAGNETIC CATCH Axel W. Ahlgren, Rockford, Ill., assignor to Amerock Corporation, Rockford, 111., a corporation of Illinois Filed Oct. 21, 1957, Ser. No. 691,437 1 Claim. (Cl. 292-2515) This invention relates to a magnetic catch for holding a door closed and other similar purposes and, more particularly, to a magnetic catch in which flat plates are disposed on opposite sides of and project beyond the edges of a fiat permanent magnet to constitute the pole pieces for the magnet, the entire magnetic assembly being enclosed in a casing.

The general object of the invention is to provide a new and improved catch of the above character which substantially eliminates the danger of the magnet breaking from shock resulting from the door being slammed, which at the same time permits the pole pieces to become alined automatically with a cooperating strike as an incident to the closing of the door, and which is comparatively simple and inexpensive in construction.

The general object is to construct and assemble the parts of the catch in a novel manner so that the magnet may be a solid block and so that the forces are transmitted to the magnet along the outer edges thereof.

A more detailed object is to hold the parts in place by surfaces which are formed on the casing and the plates to prevent edgewise shifting of the plates relative to the casing and by projections which are formed on the plates and engage the edges of the magnet to prevent the magnet from shifting out from between the plates.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which FIGURE 1 is a fragmentary side elevation of a cabinet and a magnetic catch embodying the novel features of the present invention, parts being broken away and shown in section.

FIG. 2 is a fragmentary plan view.

FIG. 3 is an enlarged perspective view of the catch.

FIG. 4 is a side view of the catch.

FIG. 5 is an exploded perspective view of parts of the catch.

FIG. 6 is a plan view of the catch as used in conjunction with a difierent type of door.

As shown in the drawings for the purposes of illustration, the invention is embodied in a magnetic catch 10 for holding a door such as a cabinet door 11 closed. The catch may be mounted on a stationary part of the cabinet such as a shelf 12 (FIGS. 1 and 2) and cooperates with a strike 13 secured to the inside of the door. Alternatively, the catch may be mounted in the door opening on the edge of the door frame 14 as illustrated in FIG. 6.

Herein, the catch includes a flat rectangular permanent magnet 15 which may be made of any suitable magnetic material such as those sold under the trade names of Alnico and Indox. Flat rectangular plates 16 of magnetic material are disposed on opposite sides of the magnet to constitute the pole pieces therefor and these plates are wider than the magnet to provide overhanging edge portions 17 which terminate in pole faces 18. The latter face the strike 13, which is a flat plate of magnetic material, so that they engage the strike when the door 11 is closed. This completes a flux path through the magnet, the pole plates and the strike and thus holds the door closed.

The pole plates 16 and the magnet 15 are enclosed by a casing 19 which extends along the outer sides of the plates and across the ends of the plates and the magnet.

As shown in the drawings, the casing is composed of two sheet metal strips 20 and 21 each made of a nonmagnetic material. The strip 20 lies against the outer side of one of the pole plates and is bent down to extend across the ends of the plates and the magnet while the strip 21 extends across the outer side of the other plate. The ends of the strip 20 terminate in lateral flanges 22 which overlie the end portions 23 of the strip 21. The flanges 22 and the end portions 23 are formed with alined slots 24 which receive screws 25 for mounting the catch 10, the slots being elongated to permit adjustment of the catch. Ribs 26 (FIG. 5) formed on the end portions 23 project through the slots in the flanges 22 and are upset to fasten the strip 21 to the strip 20.

In accordance with the present invention, the magnet 15, the pole plate 16 and the casing 19 are held together in a novel manner which permits the pole faces 18 to become alined with the strike 13 automatically as an incident to the closing of the door, which substantially eliminates the danger of breaking the magnet from the shock resulting from the door being slammed, and which is comparatively simple and inexpensive in construction. To these ends, surfaces 27 and 28 (FIG. 5) are formed on the casing and the plates respectively and cooperate to prevent the plates from shifting edgewise out of the casing. Projections 29 formed on the edge portions 17 of the plates 16 engage the edges of the magnet 15 to prevent the magnet from shifting edgewise out from between the plates. Thus, the surfaces 27 and 28 together with the projections 29 are efiective to hold the magnetic assembly within the casing.

In the present instance, the surfaces 28 are the walls of holes 30 which extend through the centers of the pole plates 16. Bosses 31 project inwardly from the strips 20 and 21 and into the holes 30 to provide the surfaces 27. The bosses 31 and the holes 30 are round to permit the plates 16 to turn slightly within the casing so that the pole faces may lie flat against the strike, a small amount of clearance being left between the ends of the plates and the casing 19 to permit such turning. In other words, the strike, when it engages the plates, turns the latter until the pole faces are in full contact with the strike.

The projections 29 may be in the form of arcuate cars which are struck laterally from the edge portions of the plates 16. The inner edges of the ears are flat and engage the edges of the magnet to prevent the latter from sliding out from between the pole plates. With this arrangement, there is no need to form any holes, recesses or the like in the magnet 15 and thus there is nothing which tends to reduce the ability of the magnet to withstand shock. Instead, the magnet is simply a solid block. All of the shock resulting from the door 11 being closed is transmitted through the cars 29 and is applied to the edges of the magnet. Under these conditions, the mag net is capable of withstanding any shock it receives during service use without cracking, breaking or shattering.

In accordance with another aspect of the invention, the casing 19 is constructed in a novel manner to compensate for variations in the thickness of the magnets 15 from catch to catch. For this purpose, the strip 21 is made of a resilient material and its central portion 32 is bowed inwardly to bear yieldably against the outer side of the lower plate 16. In assembling the casing, the bowed portion of the strip 21 straightens out somewhat as it is vbrought into place and attached to the strip 20. The

amount of such straightening depends upon the thickness of the magnet and, in this way, the resilient strip permits variations in the magnet thickness.

It will be observed that a magnetic catch constructed in accordance with the invention is comparatively simple and inexpensive to manufacture and, at the same time, it

3 is durable in service use. The surfaces 27 and 28 together with the ears 29 hold the parts securely within the casing 19 Without inducing breakage of the magnet and While still permitting limited turning of the pole plates 16 to permit the pole faces 18 to become alined with the strike 13.

I claim as my invention:

A catch comprising a generally flat rectangular permanent magnet, two flat rectangularplates of magnetic material disposed on opposite sides'of said magnet to constitute pole pieces therefor, a casing made of nonmagnetic material and comprising a first strip having a portion lying flat against the outer side of one of said plates and integral portions extending across the ends of said plates and said magnet and a second resilient strip having its ends attached to the ends of the first strip and its central portion yieldably engaging the outer side of the other References Cited in the file of this patent UNITED STATES PATENTS 2,701,158 Schmitt Feb. 1, 1955 2,770,759 Ahlgren Nov. 13, 1956 2,837,366 Loeb June 3, 1958 2,862,752 Heppner Dec. '2, 1958 2,896,991 Martin July 28, 1959 2,935,352 Heppner May 3, 1960 2,962,318 Teetor Nov. 29, 1960 

